508 BC: office of pontifex maximus (high priest) created when these powers are stripped from the consuls; possible second siege of Rome by Etruscans : Roman-Etruscan Wars
504 BC: Consul Publius Valerius Publicola grants due process rights to all Roman citizens, criminalizes all future attempts to plot to seize a tyranny
366 BC: Patricians agree to allow Plebeian Consuls to be elected (the first being Lucius Sextius Sextinus). By this, Plebeians acquire de facto right to be elected Censor or appointed Dictator. As a concession, the Plebeians allow the Patricians to create the offices of Praetor and Curule Aedile, and allow only Patricians to run for these offices.
83/82 BC– First Roman civil war, between Sulla and the popular faction; Sulla wins and becomes dictator; censor office abolished (to be recreated in 70 BC)
58/50 BC– Caesar fights the Gallic Wars, acquiring the province of Gallia Comata
54/53 BC– First campaign against the Parthian Empire; Crassus utterly defeated and killed
49 BC– Caesar crosses the Rubicon (alea iacta est) and begins the Second Roman civil war against the Optimates, the conservative faction of the Senate, led by Pompey
48/45 BC– Caesar pursues and defeats the Optimates in Greece and Africa
69– Year of the Four Emperors: after the assassination of Galba, Otho and Vitellius briefly become emperors before Vespasian's accession to power in the end of the year; Flavian dynasty begins
235– Alexander killed in a soldier mutiny. Maximinus Thrax becomes emperor.
238– Year of the Six Emperors. The Senate supports a revolt of Gordian I and Gordian II in Africa. These two are defeated by an ally of Thrax, and the Senate appoints Balbinus and Pupienus as co-emperors. They are soon assassinated, and Thrax is killed in a mutiny. The young Gordian III becomes emperor.
241– Victory over the Persians at Resaina.
244– Romans defeated at Misiche. Philip the Arab becomes emperor.
249– Decius usurps the throne with support from the Danubian legions. He names his son Herennius co-emperor.
251– Decius and Herennius defeated and slain by Cniva, king of the Goths. Another son of Decius, Hostilian, is briefly emperor, but dies in a plague outbreak. Gallus and his son Volusianus become emperors.
253– Aemilianus becomes emperor after leading a revolt and Gallus and Volusianus are slain by their own troops. Valerian and his son Gallienus become emperors after Aemilianus is killed by his own soldiers. Shapur captures Antioch.
260– Valerian is taken captive by the Persians. Retreating Persian army attacked by Odaenathus of Palmyra. Postumus proclaimed emperor in Gaul. He is also supported in Hispania and Britain.
267– Odaenathus assassinated. His widow Zenobia takes control of Palmyra
268– Gallienus defeats Gothic invasion, but is later assassinated. Claudius II becomes emperor.
269– Postumus is killed. Victorinus proclaimed emperor in Gaul and Britain. The Palmyrenes takes Egypt and Syria. Claudius defeats the Goths at Naissus in Moesia.
270– Claudius dies of plague. After a brief rule by Claudius' brother Quintillus, Aurelian becomes emperor.
271– Aurelian campaigns against the Vandals, Juthungi and the Sarmatians. Victorinus is murdered and his soldiers proclaim Tetricus I emperor
272– Aurelian defeats Zenobia at Antioch and Emesa and takes Palmyra. Zenobia is captured. The province of Dacia is abandoned.
273– Palmyra revolts. The city is destroyed by Aurelian.
274– Aurelian defeats the army of Tericus at the Catalaunian fields.
275– Aurelian is murdered. Tacitus becomes emperor.
276– Tacitus dies. After the brief reign and assassination of Florianus, Probus becomes emperor.
277– The Burgundians, Longiones, Alemanni and Franks defeated.
279– Probus campaigns against the Vandals in Illyricum.
282– Carus proclaimed emperor. Probus killed by his own troops.
283– Carus dies during an invasion of Persia. His sons Carinus and Numerian become emperors.
284– Numerian dies. Diocletian proclaimed emperor and marches against Carinus.
285– Carinus dies in battle against Diocletian. Diocletian splits the empire into two halves and appoints Maximian emperor of the Western portion while Diocletian rules the East.
303– Diocletian orders the persecution of Christians.
305– Diocletian and Maximian abdicate. Constantius and Galerius becomes Augusti. Maximinus is appointed Caesar in the east and Severus in the west.
306– Constantius dies at York. His son Constantine I proclaimed emperor. Maxentius, son of Maximian, proclaims himself emperor in Rome.
307– Maxentius reinvests his father Maximian as emperor. Severus is put to death. Galerius lays siege to Rome.
308– Conference of Carnuntum. Diocletian convinces Maximian to step down. Licinius appointed Caesar in the East.
310– Maximian again proclaims himself emperor, but is captured by Constantine. He commits suicide.
311– Galerius dies at Sardica. Maximinus and Licinius split his realm between them.
312– Constantine defeats and kills Maxentius at the Milvian Bridge. Licinius marries Constantine's sister Constantia. Constantine converts to Christianity.
313– Licinus defeats Maximinus twice. Maximinus dies at Tarsus.
Constantine issues Edict of Milan, ending persecution of Christians and establishing religious toleration throughout the Empire.
314– Constantine defeats Licinius at Cibalae
317– Constantine defeats Licinius on the Campus Ardiensis. Licinius forced to cede all his European provinces except Thrace.
360– With a Persian war imminent, Constantius orders Julian to send several legions east. The troops mutiny and proclaim Julian Augustus.
361– Constantius dies of illness, naming Julian his successor. Julian openly declares himself a pagan, but his attempt at rejuvenating paganism in the empire fails.
363– Julian invades Persia, but forced to retreat, he is mortally wounded during a skirmish and dies. Jovian is proclaimed emperor.
364– Jovien dies of accidental asphyxiation. Valentinian I becomes emperor and splits the empire with his brother Valens.
375– Valentinian dies and is succeeded by Gratian as Western emperor.
384– Gratian is murdered, Valentinian II becomes emperor.
392– Valentinian II dies of apparent suicide, though murder by Arbogast is more likely. Arbogast installs the puppet Eugenius on the Western throne, but Theodosius refuses to recognize the usurper.
394– Eugenius and Arbogast are deposed and killed by Theodosius, who briefly reunites the empire for the last time.
395– Theodosius I dies, leaving the Western empire to his son Honorius and the Eastern empire to his son Arcadius.
455– Valentinian III is assassinated and succeeded by Petronius Maximus as emperor. Rome is plundered by the Vandals, and Maximus is killed during mob violence. Avitus becomes emperor of the west.
457– Avitus is deposed by the magister militumRicimer and killed. Majorian is installed as Western emperor.
461– Majorian is deposed by Ricimer. Libius Severus becomes Western emperor.
465– Libius Severus dies, possibly poisoned by Ricimer.
467– Anthemius becomes western emperor with the support of Leo I.
468– War against the Vandals by the joint forces of both empires. Naval expedition ends in failure.
472– Ricimer kills Anthemius and makes Olybrius new western emperor. Both Ricimer and Olybrius die of natural causes. Gundobad becomes magister militum in Italy.
473– Gundobad makes Glycerius new western emperor.
474– Gundobad leaves Italy to take part in a succession struggle among the Burgundians. Glycerius is deposed by Julius Nepos who proclaims himself western emperor.
475– Julius Nepos forced to flee to Dalmatia by his magister militumOrestes. Orestes proclaims his own son Romulus Augustulus as western emperor.
476– Germanic general Odoacer kills Orestes, forces Romulus Augustus to abdicate and proclaims himself King of Italy. Traditional date for the fall of the western Roman Empire. The Eastern Roman Empire (later known as the Byzantine Empire) continues on.
480– Julius Nepos, still claiming to be emperor, is killed in Dalmatia.
568– The Lombards invade Italy; no further attempts to restore the empire
607– Emperor Phocas donates The Pantheon to the Pope and has a column erected in the Forum.
640- The Roman legion of the East Roman army is disbanded, and the theme systems is introduced.
663– Constans II is the last emperor to visit Rome, and the city gradually slips out of imperial control
976- Basil II effectively becomes Emperor of the Romans after the death of John I Tzimiskes.
1014-Basil crushes Bulgarian forces in the battle of kliedion, and he is called the "Father of the army" by his troops.
1025-The eastern Roman empire is at its peak in the eleventh century, regaining its foothold in the Balkans and southern Italy. Yet marks the death of Basil II.
1071- The battle of manzikert devastated Byzantine forces in Anatolia losing the themata and tagmata to the Seljuk Turks.
1204– Crusaders sack Constantinople and establish the Latin Empire of Constantinople.
1261– Michael VIII Palaiologos recovers Constantinople from the Latin Empire.
1453– Constantinople falls to the Ottoman Turks. End of the Byzantine/eastern Roman Empire.
1461– Trebizond falls to the Ottoman Turks. End of the Empire of Trebizond and of the last remnant of the Roman Empire.
